Has any one ever made bets with friends over stupid stuff with the result in there loss and having to do something like wear a diaper for a day?

Amongst my diaper-related foibles when I was younger (7-12 years of age), there were incidents during sleepovers where Truth-or-Dare-type games involved diapers from younger family members present in the household, but nothing like wearing them outside of the bedroom.

I had always been uneasy about that, actually, it wasn't until I was 23 when I finally went outdoors while padded; not for any reason related to gratification, humiliation or thrills, but because it was to collect pizzas from the local restaurant and it meant now the pizza wouldn't get cold while I got changed after I got back.

Has any one ever made bets with friends over stupid stuff with the result in there loss and having to do something like wear a diaper for a day?

No for two reasons:
1) I really don't get anything out of making someone else participate in diaper wearing.
2) Even though I don't have any desire to see other people wear, imagine how a friend would feel if they found out you were a DL and there had been some instance where you made them wear diapers over a lost bet or something. I know if the roles were reversed and I was caused in some way to unwittingly participate in a friends fetish, I'd feel used/creeped out/betrayed and things would be quite awkward around them (assuming I even still hung out with them after that).